U.S. Pat. No. 3,385,755 discloses antibacterial and antifungal agents derived from undecylenic acid alkylolamides. The derivatives are water soluble and are suitable for use in a variety of useful compositions, including compositions for the treatment of dandruff. One such useful derivative is the undecylenic monoalkylolamide sulfosuccinate half ester of the formula ##STR1##
Salts of the undecylenic monoalkylolamide sulfosuccinate esters are also employed in combination with 3-trifluoromethyl-4,4'-dichlorocarboanilide or 3,4,4'-trichlorocarboanilide to provide shampoo formulations effective against microorganisms normally associated with the presence of dandruff (see Japanese appln. No. SHO-42-83663 published Aug. 24,1971).
In U.S. Pat. No. 3,236,733 a method of combatting dandruff is described using pyridinethione metal salts (e.g. zinc pyridinethione) detergent compositions. German appln. No. 22 62 375 also shows the use of soluble combinations of zinc and zirconium pyrithiones to provide effective antidandruff treatment.
While the metal salts and other derivatives of 1-hydroxy-2-pyridinethione and its tautomeric form 2-pyridinethiol-1-oxide (or 2-mercaptopyridine-N-oxide) are known to be effective bacteriocides and fungicides for use in medicated shampoos for the treatment and control of dandruff, the toxicity of these compounds is relatively high and, in many instances, they are extremely irritating to the skin and eyes. The reported 24-hour acute oral lethal dosis (LD.sub.50) of zinc pyrithione is 300 mg/kg in mice and 200 mg/kg in male rats. The 24 hour acute LD.sub.50 of sodium pyrithione is approximately 1100 mg/kg in rats. A 40% solution of the sodium pyrithione does not irritate rabbit eyes but does irritate the skin. A 48% dispersion of the zinc pyrithione irritates the skin and is extremely irritating to the eyes of rabbits.